That's why Chicago's Lincoln Park Zoo has launched a project in which chimps are helping in the fight against primate heart disease.

Dr. Kathryn Gamble is the zoo's chief veterinarian, and she says heart disease has been going undetected in apes, despite a healthy diet, exercise and regular tests.

To learn more, she's using small heart monitors. They are designed for human use, but she's implanted them in eight chimps at the zoo. Three animals so far have been trained to present their chests to a scanner to upload data from the monitors.

Gamble's research may lead to new recommendations for zoos on chimpanzee diet or physical activity.